There has hitherto been known a rotation angle detector which includes a rotor having three salient poles and a stator surrounding an outer periphery of the rotor, and in which an excitation winding is wound around each of 12 teeth of the stator, and a SIN output winding and a COS output winding are alternately wound around each of the teeth in a circumferential direction of the stator (for example, see Patent Literature 1).